Polymerizable composition for a color filter

ABSTRACT

The present invention provides a polymerizable composition for a color filter, which comprises a (meth)acrylate copolymer containing alicyclic (meth)acryloyl groups in its side chains, a compound having at least one ethylenically unsaturated double bond, a photopolymerization initiator and a colorant, a color filter obtained by coating the composition on a glass substrate, followed by exposure and development; and a method for producing a color filter, which comprises coating the composition on a glass substrate, followed by exposure and development. 
     The polymerizable composition of the present invention is highly sensitive and excellent in chemical resistance. Accordingly, according to the present invention, it is possible to produce a color filter of a high quality without a protective layer such as an oxygen-shielding film.

TECHNICAL FIELD

The present invention relates to a polymerizable composition suitablefor the production of a color filter which is to be used in combinationwith a liquid crystal display device or a solid image pick-up device, acolor filter produced by using such a polymerizable composition, and amethod for its production.

BACKGROUND ART

As a color filter, one having picture elements of red, green, blue, etc.formed on a glass substrate by a dyeing method, a printing method, anelectro deposition method, a pigment dispersion method or the like, isused. A color filter by a dyeing method is produced in such a mannerthat an image is formed by a photosensitive resin prepared by mixing adichromate as a photosensitive material to gelatin or polyvinyl alcohol,followed by dyeing. To form multi colors on the same substrate, reserveprinting steps are required, whereby there is a problem that the processtends to be complex. Further, since dyes are used, it is poor in lightresistance. The dichromate used as a photosensitive material isproblematic also from the viewpoint of prevention of pollution.

A color filter by a printing method is prepared by transferring aheat-curable or photo-curable ink onto a glass substrate by such amethod as screen printing or flexographic printing. The process issimple without necessity of dyeing or forming an image. However, ahighly fine image can not thereby be obtained, and there is a problem inflatness of the ink.

A color filter by an electro deposition method is prepared by immersinga glass substrate provided with electrodes, in a bath containing apigment or dye, whereby a color phase is deposited on the substrate byelectrophoresis. It is excellent in flatness, but it is difficult toform a complicated pattern, since it is necessary to provide electrodesto the glass substrate beforehand.

In the pigment dispersion method, an image is formed by a colored resisthaving a pigment dispersed in a photo-curable resin. It has a merit suchas high heat resistance or no necessity of dyeing, and it is capable offorming a highly precise image. Accordingly, this method is currentlythe most popular method for producing color filters. However, a coloredresist having a pigment dispersed in a high concentration, is used,whereby the photo curability is poor, and the sensitivity is low, andfurther, there is a serious problem in the operation efficiency, sincethe chemical resistance is also low.

In the pigment dispersion method, image formation is carried out by acolored resist having a pigment dispersed in a high concentration.Accordingly, strong light absorption takes place by the pigment, andcure-inhibition by oxygen takes place, whereby the sensitivity used tobe low. Accordingly, in order to form an image, a long period ofexposure time is required, whereby the operation efficiency is verypoor, and in order to prevent the cure-inhibition by oxygen, it isnecessary to further form a protecting film to shield oxygen on theresist film, which makes the process further complex. Further, the imageformed in such a manner is not sufficiently photo-cured, whereby theimage is poor in the heat resistance and chemical resistance, and it hasbeen necessary to protect the colored image at the time of forming apolyimide film which serves as an orientation film for liquid crystal.

An object of the present invention is to solve the above-mentionedproblems of the conventional colored resists and to provide apolymerizable composition for a color filter having a high sensitivityand being excellent in chemical resistance.

Another object of the present invention is to provide a color filter ofa high quality by using such a polymerizable composition.

The present inventors have strenuously proceeded with a research for theabove objects and as a result, have found that a polymerizablecomposition for a color filter comprising, as an organic polymermaterial, a (meth)acrylate copolymer containing alicyclic (meth)acryloylgroups in its side chains, is highly sensitive, provides a highresolution and is excellent also in chemical resistance andpigment-dispersibility. The present invention has been accomplished onthe basis of this discovery. In the present specification, "(meth)acryl. . . " and "(meth)acryloyl . . . " mean "acryl . . . or methacryl . . ." and "acryloyl . . . or methacryloyl . . . ". For example,"(meth)acrylic acid" means "acrylic acid or methacrylic acid".

DISCLOSURE OF THE INVENTION

Namely, the present invention resides in a polymerizable composition fora color filter, which comprises a (meth)acrylate copolymer containingalicyclic (meth)acryloyl groups in its side chains, a compound having atleast one ethylenically unsaturated double bond, a photopolymerizationinitiator and a colorant.

Further, the present invention resides in a color filter obtained bycoating the above polymerizable composition on a glass substrate,followed by exposure and development.

Still further, the present invention resides in a method for producing acolor filter, which comprises coating the above polymerizablecomposition on a glass substrate, followed by exposure and development.

Now, the present invention will be described in detail.

In the present invention, as the resin, a (meth)acrylate copolymerhaving alicyclic (meth)acryloyl groups as polymerizable groups in itsside chains, is used. As a synthetic means for introducing suchpolymerizable groups to a resin, a method disclosed in e.g. JapaneseExamined Patent Publication No. 34443/1975 or No. 34444/1975, is known.Specifically, a resin having polymerizable groups in its side chains,can be obtained by reacting e.g. a compound which has both a(meth)acryloyl group and an aliphatic epoxy group such as anepoxycyclohexyl group or an epoxycyclopentyl group, to carboxyl groupsor hydroxyl groups in the resin. As a preferred example of the abovecompound, epoxycyclohexylmethyl (meth)acrylate or epoxycyclopentylmethyl(meth)acrylate may be mentioned. The most preferred among them is(3,4-epoxycyclohexyl)methyl (meth)acrylate.

In the present invention, alicyclic groups are introduced in side chainsof the resin to be used as a binder, whereby it is possible to obtain apolymerizable composition for a color filter, which is excellentparticularly in adhesion and has high chemical resistance.

The resin skeleton to which (meth)acryloyl groups are introduced aspolymerizable groups, is a (meth)acrylate copolymer which may, forexample, be a copolymer prepared by copolymerizing (meth)acrylic acidwith a monomer which may, for example, be a styrene which may besubstituted by an alkyl group at the α-position, such as styrene orα-methylstyrene, methyl (meth)acrylate, ethyl (meth)acrylate, propyl(meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, vinylacetate, acrylonitrile, (meth)acrylamide, glycidyl (meth)acrylate,allylglycidyl ether, glycidyl ethyl acrylate, crotonylglycidyl ether,crotonic acid glycidyl ether, (meth)acrylic acid chloride, benzyl(meth)acrylate, hydroxyethyl (meth)acrylate, N-methylolacrylamide,N,N-dimethylacrylamide, N-methacryloylmorpholine, N,N-dimethylaminoethyl(meth)acrylate or N,N-dimethylaminoethylacrylamide. Particularlypreferred is a copolymer comprising, as copolymer components,(meth)acrylic acid and styrene which may be substituted by an alkylgroup at the α-position. The proportion of (meth)acrylic acid in thecopolymer is preferably from 0.2 to 0.8, more preferably from 0.3 to0.7, by a molar ratio. Further, the proportion of the above-mentionedcopolymer component such as styrene, in the copolymer, is preferablyfrom 0.8 to 0.2, more preferably from 0.7 to 0.3.

The weight average molecular weight, as measured by GPC, of the(meth)acrylate copolymer to be used in the present invention, ispreferably from 1,000 to 50,000. If the weight average molecular weightis less than 1,000, it tends to be difficult to obtain a uniform coatingfilm. On the other hand, if it exceeds 50,000, it tends to be unstableand tends to undergo gelation. Further, a preferred content of acidicgroups such as carboxyl groups, is at a level of from 5 to 200 by acidvalue. If the acid value is less than 5, it tends to be insoluble in analkali developing solution, and if it exceeds 200, the sensitivity maysometimes decrease.

As the photopolymerization initiator, any one of conventional initiatorsmay be employed. However, from the viewpoint of the sensitivity andchemical resistance, a combination of an imidazole compound and anaminobenzene derivative, a 2-amino-2-benzoyl-1-phenylalkane compound, ahalomethylate triazine compound or a halomethyloxadiazole, is preferred.

As a preferred imidazole compound, one having the following structure inwhich two imidazoles are bonded by one covalent bond: ##STR1## whereinAr is an aryl group which may be substituted, may be mentioned.

As the aryl group which may be substituted, a phenyl group which may besubstituted, is preferred. As the substituent on the aryl group, ahalogen atom such as a fluorine atom, a chlorine atom or a bromine atom,a nitro group, a methyl group, or a methoxy group, may, for example, bementioned. A hexaphenyl biimidazole wherein the opposition of a phenylgroup at each of the 2- and 2'-positions, is substituted by a halogenatom such as a fluorine atom, a chlorine atom or a bromine atom, a nitrogroup or a methyl group, is particularly advantageous from the viewpointof the properties such as heat stability and photo reaction rate.

Specific examples of the hexaarylbiimidazole include2,2'-bis(o-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole,2,2'-bis(o-bromophenyl)-4,4',5,5'-tetraphenylbiimidazole,2,2'-bis(o,p-dichlorophenyl)-4,4',5,5'-tetraphenylbiimidazole,2,2'-bis(o-chlorophenyl)-4,4',5,5'-tetra(m-methoxyphenyl)biimidazole,2,2'-bis(o,o'-dichlorophenyl)-4,4',5,5'-tetraphenylbiimidazole,2,2'-bis(o-nitrophenyl)-4,4',5,5'-tetraphenylbiimidazole, and2,2'-bis(o-methylphenyl)-4,4',5,5'-tetraphenylbiimidazole. Particularly,2,2'-bis(o-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole isadvantageously used.

These hexaarylbiimidazoles can readily be prepared by the methodsdisclosed in e.g. Bull. Chem. Soc. Japan, 33, 565(1960) and J. Org.Chem., 36, 2262(1971).

The aminobenzene derivative is a compound having an aminophenyl groupmoiety in its structure, and it may, for example, be a benzophenonecompound such as 4,4'-dimethylaminobenzophenone,4,4'-diethylaminobenzophenone, 2-aminobenzophenone, 4-aminobenzophenone,4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone or3,4-diaminobenzophenone, or a p-diaralkylaminophenyl group-containingcompound such as 2-(p-dimethylaminophenyl)benzoxazole,2-(p-diethylaminophenyl)benzoxazole, 2-(p-dimethylaminophenyl)benzo4,5!benzoxazole, 2-(p-dimethylaminophenyl)benzo 6,7!benzoxazole,2,5-bis(p-diethylaminophenyl)1,3,4-oxazole,2-(p-dimethylaminophenyl)benzothiazole,2-(p-diethylaminophenyl)benzothiazole,2-(p-dimethylaminophenyl)benzimidazole,2-(p-diethylaminophenyl)benzimidazole,2,5-bis(p-diethylaminophenyl)1,3,4-thiadiazole,(p-dimethylaminophenyl)pyridine, (p-diethylaminophenyl)pyridine,2-(p-dimethylaminophenyl)quinoline, 2-(p-diethylaminophenyl)quinoline,2-(p-dimethylaminophenyl)pyrimidine or2-(p-diethylaminophenyl)pyrimidine.

Particularly preferred is 4,4'-dimethylaminobenzophenone,4,4'-diethylaminobenzophenone, 2-(p-dimethylaminophenyl)benzoxazole,2-(p-dimethylaminophenyl)benzothiazole or2-(p-diethylaminophenyl)benzimidazole.

The 2-amino-2-benzoyl-1-phenylalkane compound as the photopolymerizationinitiator to be used in the present invention, is represented by theformula (1): ##STR2## wherein each of R¹, R² and R³ which areindependent of one another, is a hydrogen atom or a C₁₋₄ alkyl group,and X is a morpholino group or a SR⁴ group, wherein R⁴ is a C₁₋₆ alkylgroup or a phenyl group.

The compounds of the following formulas (2) to (9) may be mentioned asspecific examples of the 2-amino-2-benzoyl-1-phenylalkane compound:##STR3##

Preferred among the 2-amino-2-benzoyl-1-phenylalkane compounds of theformula (1), is a compound of the same formula in which each of R¹, R²and R³ which are independent of one another, is a C₁₋₄ alkyl group, andX is a morpholino group. More preferred is a compound wherein R¹ is aC₁₋₄ alkyl group, and each of R² and R³ which are independent of eachanother, is a C₁₋₂ alkyl group.

The halomethylated triazine compound as the photopolymerizationinitiator to be used in the present invention, is represented by theformula (10): ##STR4## wherein each of R⁵ and R⁶ is a halomethyl group,and Y is an organic group having at least 5 carbon atoms. The halomethylgroup may, for example, be a trichloromethyl group, a tribromomethylgroup, a dichloromethyl group or a dibromomethyl group, and the organicgroup having at least 5 carbon atoms may, for example, be a phenylgroup, a naphthyl group, a styryl group, a styrylphenyl group, afurylvinyl group or a quaternary aminoethylamino group, which may have asubstituent.

The compounds of the following formulas (11) to (32) may be mentioned asspecific examples of the halomethylated triazine compound: ##STR5##

Preferred among the halomethylated triazine compounds of the formula(10), are compounds of the following formulas (33) to (35): ##STR6##wherein each of R⁵ and R⁶ is a halomethyl group, each R which isindependent, is a C₁₋₄ alkyl group or a C₁₋₄ alkoxy group, and n is aninteger of from 0 to 3. ##STR7## wherein each of R⁵ and R⁶ is ahalomethyl group, each R which is independent, is a C₁₋₄ alkyl group ora C₁₋₄ alkoxy group, and n is an integer of from 0 to 3. ##STR8##wherein each of R⁵ and R⁶ is a halomethyl group, each R which isindependent, is a C₁₋₄ alkyl group, and n is an integer of from 0 to 1.

Preferred among the compounds of the formulas (33) to (35), arecompounds wherein each of R⁵ and R⁶ is a trichloromethyl group, thecarbon number of R is 1 or 2, and n is an integer of from 0 to 2 in thecase of the formulas (33) and (34) and an integer of from 0 to 1 in thecase of the formula (35).

The halomethylated oxadiazole compound as the photopolymerizationinitiator to be used in the present invention, is represented by theformula (36): ##STR9## wherein R⁷ is a halomethyl group, and Z is abenzofuryl group or a benzofurylvinyl group which may have asubstituent.

Compounds of the following formulas (37) to (54) may be mentioned asspecific examples of the halomethylated oxadiazole compound: ##STR10##

Preferred among the halomethylated oxadiazole compounds of the formula(36), is a compound of the following formula (55): ##STR11## wherein R⁷is a halomethyl group, each R which is independent, is a C₁₋₄ alkylgroup or a C₁₋₄ alkoxy group, and n is an integer of from 0 to 2. Morepreferred is a compound wherein R⁷ is a trichloromethyl group, each Rwhich is independent, is a C₁₋₂ alkyl group or a C₁₋₂ alkoxy group, andn is an integer of from 0 to 1.

In addition to the foregoing photopolymerization initiator, a hydrogendonative compound such as 2-mercaptobenzothiazole, 2-mercaptobenzoxazoleor 2-mercaptobenzimidazole, may be incorporated to further improve thesensitivity and adhesion.

The compound having at least one ethylenically unsaturated double bond,to be used as a photopolymerizable monomer, is preferably a compoundcontaining at least one, more preferably at least 3, acryloyl groups,but it is not restricted thereto. Specifically, it may, for example, beisobutyl acrylate, t-butyl acrylate, lauryl acrylate, cetyl acrylate,stearyl acrylate, cyclohexyl acrylate, isobonyl acrylate, benzylacrylate, 2-methoxyethyl acrylate, 3-methoxybutyl acrylate,ethylcarbitol acrylate, phenoxyethyl acrylate, tetrahydrofuryl acrylate,phenoxypolyethylene glycol acrylate, methoxypropylene glycol acrylate,hydroxyethyl acrylate, 2-hydroxypropyl acrylate,2-acryloyloxyethylhydrogen phthalate, 2-acryloyloxypropylhydrogenphthalate, 2-acryloyloxypropylhydrogen phthalate,2-acryloyloxypropyltetrahydrohydrogen phthalate, morpholinoethylmethacrylate, trifluoroethyl acrylate, trifluoroethyl methacrylate,tetrafluoropropyl (meth)acrylate, hexafluoropropyl (meth)acrylate,octafluoropentyl (meth)arylate, heptadecafluorododecyl acrylate,trimethylcyclohexylethyl methacrylate, 1,4-butanediol diacrylate,1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, neopentyl glycoldiacrylate, tetraethylene glycol diacrylate, tripropylene glycoldiacrylate, propylene glycol diacrylate, glycerol methacrylate acrylate,bisphenol A, an EO adduct diacrylate, trimethylol propane triacrylate,pentaerythritol triacrylate, pentaerythritol tetraacrylate,trimethylolpropane EO-added triacrylate, glycerol PO-added triacrylate,trisacryloyloxyethyl phosphate, dipentaerythritol hexaacrylate, anovolak epoxy acrylic acid-modified product, a novolak epoxy acrylicacid and acid anhydride-modified product, N-vinylpyrrolidone,N-vinylcaprolactam, acrylic isocyanurate, dipentaerythritol monohydroxypentaacrylate, urethane acrylate or an unsaturated polyester acrylate.Among these monomers, an at least trifunctional acrylate monomer ispreferred. These monomers may be used alone or in combination as amixture of a plurality of them.

The pigment may, for example, be an inorganic pigment such as bariumsulfate, lead sulfate, titanium oxide, yellow lead oxide, iron oxidered, chromium oxide or carbon black, or an organic pigment such as ananthraquinone pigment, a perylene pigment, a disazo pigment, aphthalocyanine pigment, an isoindoline pigment, a dioxazine pigment, aquinacridone pigment, a perynone pigment, a triphenylmethane pigment ora thioindigo pigment. These pigments may be used alone or in admixture.Specifically, pigments represented by the following color index (C.I)numbers, may, for example, be mentioned.

C.I. red: 9, 97, 122, 123, 149, 168, 177, 180, 192, 215, 216, 217, 220,223, 224, 226, 227, 228, 240

C.I. blue: 15, 15; 6, 22, 60, 64

C.I. green: 7, 36

C.I. black: 7

C.I. yellow: 20, 24, 86, 93, 109, 110, 117, 125, 137, 138, 147, 148,153, 154, 166, 168

C.I. orange: 36, 43, 51, 55, 59, 61

C.I. violet: 19, 23, 29, 30, 37, 40, 50

C.I. brown: 23, 25, 26

It is particularly preferred to use, as the pigment, at least one memberselected from the group consisting of an anthraquinone pigment, aphthalocyanine pigment, an azo pigment, a dioxazine pigment and carbonblack.

Further, with a colored resist having a black pigment such as carbonblack dispersed to form a black matrix, there has been a problem thatthe dispersibility of the pigment is poor, the operation efficiency forcoating is poor, foreign matters are likely to remain on the resistfilm, or pin hole defects are likely to form. However, the(meth)acrylate copolymer having alicyclic (meth)acryloyl groups in itsside chains, is capable of having a black pigment, particularly carbonblack, dispersed very well, so that foreign matters on the resist filmwill be little, it is possible to form a black matrix of a high quality,and it is possible to present a color filter of a high quality.

The average particle size of such a pigment is preferably within a rangeof from 0.005 to 0.5 μm, more preferably from 0.01 to 0.3 μm. If theaverage particle size is lower than this range, thixotropic propertiesare likely to result, whereby excellent coating properties can hardly beobtained. On the other hand, if it exceeds the above range, the coatingfilm tends to be poor in transparency. To attain such a particle size, aball mill, a sand mill, a beads mill, a three roll mill, a paint shakeror a dispersion treatment by means of supersonic waves, is effective.

The solvent may specifically be an organic solvent such as diisopropylether, mineral spirit, n-pentane, amyl ether, ethyl caprylate, n-hexane,diethyl ether, isoprene, ethyl isobutyl ether, butyl stearate, n-octane,Varsol #2, Apco #18 solvent, diisobutylene, amyl acetate, butylbutyrate, Apco thinner, butyl ether, diisobutyl ketone, methylcyclohexene, methyl nonyl ketone, propyl ether, dodecane, Socal solventNo. 1 and No. 2, amyl formate, dihexyl ether, diisopropyl ketone,Solveso #15, (n, sec, t)-butyl acetate, hexene, Shell TS28 solvent,butyl chloride, ethyl amyl ketone, ethyl benzoate, amyl chloride,ethylene glycol diethyl ether, ethyl orthoformate,methoxymethylpentanone, methyl butyl ketone, methyl hexyl ketone, methylisobutyrate, benzonitrile, ethyl propionate, methyl cellosolve acetate,methyl isoamyl ketone, methyl isobutyl ketone, propyl acetate, amylacetate, amyl formate, bicyclohexyl, diethylene glycol monoethyl etheracetate, dipentene, methoxymethylpentanol, methyl amyl ketone, methylisopropyl ketone, propyl propionate, propylene glycol t-butyl ether,methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, ethylcellosolve acetate, carbitol, cyclohexanone, ethyl acetate, propyleneglycol, propylene glycol monomethyl ether, propylene glycol monomethylether acetate, propylene glycol monoethyl ether, propylene glycolmonoethyl ether acetate, dipropylene glycol monoethyl ether, dipropyleneglycol monomethyl ether, propylene glycol monoethyl ether acetate,dipropylene glycol monomethyl ether acetate, 3-methoxypropionic acid,3-ethoxypropionic acid, methyl 3-ethoxypropionate, methyl3-methoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid,propyl 3-methoxypropionate, butyl 3-methoxypropionate, diglyme,dipropylene glycol monomethyl ether, ethylene glycol acetate,ethylcarbitol, butylcarbitol, ethylene glycol monobutyl ether, propyleneglycol t-butyl ether, 3-methyl-3-methoxybutanol, tripropylene glycolmethyl ether or 3-methyl-3-methoxybutyl acetate.

The solvent is preferably selected among those having boiling pointswithin a range of from 100° C. to 200° C. More preferably, it is the onehaving a boiling point of from 120° C. to 170° C. Such solvents may beused alone or in admixture. Propylene glycol methyl ether acetate can beused particularly advantageously.

The proportions of the respective components used for the polymerizablecomposition for a color filter of the present invention vary dependingupon the types of the compounds to be used. However, usually, thephotopolymerization initiator is incorporated in an amount within arange of from 0.05 to 50 parts by weight, preferably from 0.05 to 30parts by weight, the photopolymerizable monomer from 5 to 200 parts byweight, the pigment from 10 to 500 parts by weight, preferably thesolvent from 200 to 500 parts by weight, per 100 parts by weight of the(meth)acrylate copolymer having (meth)acryloyl groups in its sidechains. Further, the content (P) of the pigment is preferably such thatP/V i.e. the ratio to the solid content (V) other than the pigment, iswithin a range of from 0.15 to 0.60. However, in a case of apolymerizable composition for black matrix containing a black pigmentsuch as carbon black, it is advisable that P/V is within a range of from0.5 to 1.5, preferably from 0.7 to 1.4, most preferably from 0.9 to 1.3,in order to form a black matrix with an optical density of at least 2.5,preferably at least 3.0, as a coating film formed in a film thickness ofat most 1.0 μm, preferably from 0.3 to 0.9 μm, more preferably from 0.4to 0.8 μm.

If the content of the photopolymerization initiator is less than theabove range, no adequate sensitivity tends to be obtained, and if itexceeds the above range, the internal curing property tends to be poor,and in some cases, the initiator undergoes recrystallization andprecipitates. If the amount of the monomer is less than the above range,the crosslinking density of an image portion subjected to exposure tendsto be inadequate, whereby a good image tends to be hardly obtainable. Onthe other hand, if it exceeds the above range, stickiness of the resistfilm after drying tends to be substantial, whereby the operationefficiency tends to be poor. If the amount of the pigment is less thanthe above range, it tends to be difficult to attain a color densityrequired for the preparation of color filter, and if it exceeds theabove range, light absorption by the pigment tends to be too much,whereby internal photocuring will not take place, and a desired imagewill not be obtained. If the amount of the solvent is less than theabove range, a photosensitive solution tends to be highly viscous,whereby the coating irregularity is likely to result, whereby the filmthickness tends to be non-uniform, and the operation efficiency tends tobe poor. If it exceeds the above range, no adequate film thickness tendsto be obtained, and coating defects such as pin holes are likely toform.

In the present invention, in addition to the above essential components,it is possible to incorporate a sensitizer, a pigment-dispersionassisting agent, a coating property-improving agent, a crosslinkingagent, a development-improving agent, a polymerization inhibitor, aplasticizer, a flame retardant, etc. These additives may be used aloneor in combination of a plurality of them.

The composition of the present invention may be coated on a glasssubstrate by a conventional means such as a spin coater, a roll coater,a curtain coater or a screen printing. The coating film thickness ispreferably from 0.5 μm to 10 μm. To dry the coating film, a convectionoven or a hot plate is used. The drying temperature is from 50° C. to150° C., and the drying time is preferably from 30 seconds to 60minutes. For exposure, a high pressure mercury lamp is usually employed,and by exposure through a mask, a latent image will be formed by aresist film. By development with a solvent capable of dissolving anon-exposed portion, an image will be formed. As the developer, anorganic solvent such as acetone, toluene or methyl ethyl ketone may beused. However, an alkali developing solution is preferred in view of anenvironmental problem. For example, an aqueous sodium hydroxidesolution, an aqueous potassium hydroxide solution, an aqueous sodiumcarbonate solution, an aqueous potassium carbonate solution, aqueousammonia, or an aqueous tetramethylammonium hydroxide solution may beemployed. The development method is not particularly limited, anddevelopment can be carried out by a conventional method such as apaddling method, a dipping method or a spraying method. Further,prewetting may be employed. For the purpose of drying the developingsolution after forming an image or increasing the curing of a resistfilm, post baking or post photocuring may, for example, be employed.

BEST MODE FOR CARRYING OUT THE INVENTION

Now, the present invention will be described in detail with reference toExamples. However, the present invention is by no means restricted bythe following Examples unless it does not exceed the gist of the presentinvention.

PREPARATION EXAMPLE 1

20 g of a styrene/acrylic acid resin having an acid value of 200 and amolecular weight of 5,000, 0.2 g of p-methoxyphenol, 0.2 g ofdodecyltrimethylammonium chloride and 40 g of propylene glycolmonomethyl ether acetate, were charged into a flask, and 7.6 g of(3,4-epoxycyclohexyl)methyl acrylate was dropwise added thereto, and themixture was reacted at a temperature of 100° C. for 30 hours. Thereaction solution was re-precipitated in water and dried to obtain aresin. Neutralization titration was carried out with KOH, whereby theacid value of the resin was 80.

PREPARATION EXAMPLE 2

20 g of a styrene/acrylic acid resin having an acid value of 200 and amolecular weight of 5,000, 0.2 g of p-methoxyphenol, 0.2 g ofdodecyltrimethylammonium chloride and 40 g of propylene glycolmonomethyl ether acetate, were charged into a flask, and 7.7 g of acompound of (3,4-epoxycyclohexyl)methyl methacrylate was dropwise addedthereto. The mixture was reacted at a temperature of 100° C. for 30hours. The reaction solution was re-precipitated in water and dried toobtain a resin. Neutralization titration by KOH was carried out, wherebythe acid value of the resin was 80.

PREPARATION EXAMPLE 3

20 g of a styrene/acrylic acid resin having an acid value of 200 and amolecular weight of 5,000, 0.2 g of p-methoxyphenol, 0.2 g ofdodecyltrimethylammonium chloride and 40 g of propylene glycolmonomethyl ether acetate, were charged into a flask, and 5.9 g ofglycidyl methacrylate was dropwise added thereto. The mixture wasreacted at a temperature of 100° C. for 30 hours. The reaction solutionwas re-precipitated in water and dried to obtain a resin. Neutralizationtitration was carried out with KOH, whereby the acid value of the resinwas 80.

EXAMPLES 1 to 22 and COMPARATIVE EXAMPLES 1 to 32

To 100 parts by weight of a resin as identified in Table 1, aphotopolymerization initiator as identified in Table 1 (in an amount asidentified in Table 1), 50 parts by weight of dipentaerythritolhexaacrylate as a photopolymerizable monomer, 70 parts by weight ofphthalocyanine blue (C.I 15;6) as a pigment and 1000 parts by weight ofpropylene glycol monomethyl ether acetate as a solvent, were added andthoroughly mixed to obtain a photosensitive liquid for a color filter.In the Table, the numbers for the initiator represent the followingcompounds.

b-1: 2,2'-bis(o-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole

b-2: 4,4'-dimethylaminobenzophenone

b-3: 4,4'-diethylaminobenzophenone

b-4: 2-(p-dimethylaminophenyl)benzoxazole

b-5: 2-(p-dimethylaminophenyl)benzothiazole

b-6: 2-(p-diethylaminophenyl)benzimidazole

b-7: compound of the above-mentioned formula (3)

b-8: compound of the above-mentioned formula (11)

b-9: compound of the above-mentioned formula (12)

b-10: compound of the above-mentioned formula (13)

b-11: compound of the above-mentioned formula (14)

b-12: compound of the above-mentioned formula (37)

The evaluation methods for the photosensitive liquids are as follows.

Each photosensitive liquid was coated on a glass substrate by a spincoater and dried on a hot plate for one minute, the thickness of theresist film was 1.5 μm. This sample was subjected to image exposurethrough a mask by a high pressure mercury lamp and then immersed in a 1%potassium carbonate aqueous solution at a developing temperature of 25°C. for one minute to obtain a resist pattern. The sensitivity of theresist was represented by the quantity of exposure with which the resistpattern was finished exactly with the image size of the mask. Further,the resolution was represented by the minimum size of the resist patternthereby formed.

In the chemical resistance test, the developed sample was furtherheat-cured in a convection oven at 200° C. for 30 minutes and thenimmersed in N-methylpyrrolidone at room temperature for 30 minutes,whereupon the state of the resist film was visually observed andevaluated. The results are shown in Table 2.

                                      TABLE 1    __________________________________________________________________________           Resin   Amount of initiator    __________________________________________________________________________    Example 1           Prep. Example 1                   b-1 (10 parts by weight)                                  b-2  (5 parts by weight)    Example 2           Prep. Example 1        b-3  (5 parts by weight)    Example 3           Prep. Example 1        b-4  (5 parts by weight)    Example 4           Prep. Example 1        b-5  (5 parts by weight)    Example 5           Prep. Example 1        b-6  (5 parts by weight)    Example 6           Prep. Example 1                   b-7  (10 parts by weight)    Example 7           Prep. Example 1                   b-8  (10 parts by weight)    Example 8           Prep. Example 1                   b-9  (10 parts by weight)    Example 9           Prep. Example 1                   b-10 (10 parts by weight)    Example 10           Prep. Example 1                   b-11 (10 parts by weight)    Example 11           Prep. Example 1                   b-12 (10 parts by weight)    Example 12           Prep. Example 2                   b-1 (10 parts by weight)                                  b-2  (5 parts by weight)    Example 13                    b-3  (5 parts by weight)    Example 14                    b-4  (5 parts by weight)    Example 15                    b-5  (5 parts by weight)    Example 16                    b-6  (5 parts by weight)    Example 17     b-7  (10 parts by weight)    Example 18     b-8  (10 parts by weight)    Example 19     b-9  (10 parts by weight)    Example 20     b-10 (10 parts by weight)    Example 21     b-11 (10 parts by weight)    Example 22     b-12 (10 parts by weight)    Comp. Ex. 1           Styrene/acrylic                   Benzophenone (10 parts by weight)    Comp. Ex. 2           acid resin                   Acetophenone (10 parts by weight)    Comp. Ex. 3           acid value: 200                   Benzylmethylketal (10 parts by weight)    Comp. Ex. 4           Mw: 5,000                   4-Dimethylaminoisoamyl benzoate (10 parts by weight)    Comp. Ex. 5    4-Diethylaminoethyl benzoate (10 parts by weight)    Comp. Ex. 6    2,4-Diethylthioxantone (10 parts by weight)    Comp. Ex. 7    3,3-Dimethyl-4-methoxybenzophenone (10 parts by weight)    Comp. Ex. 8    1-Hydroxy-cyclohexyl-phenyl ketone (10 parts by weight)    Comp. Ex. 9    2-Methyl-1-(4-(thiophenyl)-2-morpholino)propane (10 parts                   by weight)    Comp. Ex. 10   2-Hydroxy-2-methyl-1-phenylpropan-1-one (10 parts by                   weight)    Comp. Ex. 11   2,2-Dimethoxy-1,2-diphenylethan-1-one (10 parts by                   weight)    Comp. Ex. 12   b-7  (10 parts by weight)    Comp. Ex. 13   b-8  (10 parts by weight)    Comp. Ex. 14   b-9  (10 parts by weight)    Comp. Ex. 15   b-10 (10 parts by weight)    Comp. Ex. 16   b-11 (10 parts by weight)    Comp. Ex. 17           Prep. Example 3                   Benzophenone (10 parts by weight)    Comp. Ex. 18   Acetophenone (10 parts by weight)    Comp. Ex. 19   Benzylmethylketal (10 parts by weight)    Comp. Ex. 20   4-Dimethylaminoisoamyl benzoate (10 parts by weight)    Comp. Ex. 21   4-Diethylaminoethyl benzoate (10 parts by weight)    Comp. Ex. 22   2,4-Diethylthioxantone (10 parts by weight)    Comp. Ex. 23   3,3-Dimethyl-4-methoxybenzophenone (10 parts by weight)    Comp. Ex. 24   1-Hydroxy-cyclohexyl-phenyl ketone (10 parts by weight)    Comp. Ex. 25   2-Methyl-1-(4-(thiophenyl)-2-morpholino)propane (10 parts                   by weight)    Comp. Ex. 26   2-Hydroxy-2-methyl-1-phenylpropan-1-one (10 parts by                   weight)    Comp. Ex. 27   2,2-Dimethoxy-1,2-diphenylethan-1-one (10 parts by                   weight)    Comp. Ex. 28   b-7  (10 parts by weight)    Comp. Ex. 29   b-8  (10 parts by weight)    Comp. Ex. 30   b-9  (10 parts by weight)    Comp. Ex. 31   b-10 (10 parts by weight)    Comp. Ex. 32   b-11 (10 parts by weight)    __________________________________________________________________________

                  TABLE 2    ______________________________________                                 Chemical             Sensitivity                        Resolution                                 resistance    ______________________________________    Example 1   100 mj      <10μ  ◯    Example 2   100 mj      <10μ  ◯    Example 3   100 mj      <10μ  ◯    Example 4   100 mj      <10μ  ◯    Example 5   100 mj      <10μ  ◯    Example 6   500 mj      <10μ  ◯    Example 7   500 mj      <10μ  ◯    Example 8   500 mj      <10μ  ◯    Example 9   500 mj      <10μ  ◯    Example 10  500 mj      <10μ  ◯    Example 11  500 mj      <10μ  ◯    Example 12  120 mj      <10μ  ◯    Example 13  120 mj      <10μ  ◯    Example 14  120 mj      <10μ  ◯    Example 15  120 mj      <10μ  ◯    Example 16  120 mj      <10μ  ◯    Example 17  600 mj      <10μ  ◯    Example 18  600 mj      <10μ  ◯    Example 19  600 mj      <10μ  ◯    Example 20  600 mj      <10μ  ◯    Example 21  600 mj      <10μ  ◯    Example 22  600 mj      <10μ  ◯    Comp. Ex. 1               >5000 mj     50μ   X    Comp. Ex. 2               >5000 mj     50μ   X    Comp. Ex. 3               >5000 mj     50μ   X    Comp. Ex. 4               >5000 mj     50μ   X    Comp. Ex. 5               >5000 mj     50μ   X    Comp. Ex. 6               >5000 mj     50μ   X    Comp. Ex. 7               >5000 mj     50μ   X    Comp. Ex. 8               >5000 mj     50μ   X    Comp. Ex. 9               >5000 mj     50μ   X    Comp. Ex. 10               >5000 mj     50μ   X    Comp. Ex. 11               >5000 mj     50μ   X    Comp. Ex. 12                1000 mj     50μ   X    Comp. Ex. 13                1000 mj     50μ   X    Comp. Ex. 14                1000 mj     50μ   X    Comp. Ex. 15                1000 mj     50μ   X    Comp. Ex. 16                1000 mj     50μ   X    Comp. Ex. 17               >5000 mj     20μ   Δ    Comp. Ex. 18               >5000 mj     20μ   Δ    Comp. Ex. 19               >5000 mj     20μ   Δ    Comp. Ex. 20               >5000 mj     20μ   Δ    Comp. Ex. 21               >5000 mj     20μ   Δ    Comp. Ex. 22               >5000 mj     20μ   Δ    Comp. Ex. 22               >5000 mj     20μ   Δ    Comp. Ex. 23               >5000 mj     20μ   Δ    Comp. Ex. 24               >5000 mj     20μ   Δ    Comp. Ex. 25               >5000 mj     20μ   Δ    Comp. Ex. 26               >5000 mj     20μ   Δ    Comp. Ex. 27               >5000 mj     20μ   Δ    Comp. Ex. 28                800 mj      20μ   Δ    Comp. Ex. 29                800 mj      20μ   Δ    Comp. Ex. 30                800 mj      20μ   Δ    Comp. Ex. 31                800 mj      20μ   Δ    Comp. Ex. 32                800 mj      20μ   Δ    ______________________________________     ◯: Resist film not peeled at all.     X: Resist film entirely peeled.     Δ: Resist film partially peeled.

As shown in Table 2, by combining a high molecular weight polymer havingpolymerizable groups in its side chains and a specificphotopolymerization initiator, it is possible to obtain a color resistcomposition excellent in the image-forming performance and chemicalresistance. In Examples, the same state as prior to immersion wasmaintained even after immersion in the solvent NMP for 30 minutes.Further, the sensitivity was higher by at least from about 1.3 to 50times than Comparative Examples. With a polymer having no polymerizablegroup in its side chains, as in Comparative Examples 1 to 16, thechemical resistance is poor, and the sensitivity is low. As inComparative Examples 17 to 32, if the side chains are changed to otherpolymerizable groups, the sensitivity deteriorates substantially, andthe chemical resistance is poor. In Comparative Examples, afterimmersion in N-methylpyrrolidone, the resist film was partially orentirely peeled from the glass substrate.

EXAMPLES 23 to 26 and COMPARATIVE EXAMPLES 33 to 38

A composition as defined in Table 3 was subjected to dispersiontreatment by a paint shaker for 10 hours to obtain a dispersed paste ofcarbon black MA-100 or MA-220, manufactured by Mitsubishi ChemicalCorporation. To such a carbon black-dispersed paste, b-1 (2 parts byweight) and b-2 (1 part by weight) as initiators, dipentaerythritolhexaacrylate (15 parts by weight) and PGMEA (450 parts by weight) wereadded to obtain a black resist composition.

Then, the black resist composition photosensitive liquid was coated on aglass substrate in a thickness of 1 μm by a spin coater and baked on ahot plate at 100° C. for 60 seconds. Foreign matters on the resistcoating film were visually observed, followed by image exposure througha mask by a high pressure mercury lamp, then immersion in a 0.05%potassium hydroxide aqueous solution at 25° C. for 30 seconds fordevelopment and rinsing with water to carry out patterning of the blackresist. The quantity of exposure with which the pattern became the samesize as the mask was taken as the sensitivity, and the minimum resistsize thereby formed was observed by a microscope and taken as theresolution. The results are shown in Table 4. As is evident fromExamples in Table 4, the composition of the present invention isexcellent in the pigment dispersibility, whereby a black matrix of ahigh quality can be obtained at a high productivity.

                                      TABLE 3    __________________________________________________________________________            Components            Resin      Carbon black                                Solvent            (25 parts by weight)                       (50 parts by weight)                                (100 parts by weight)    __________________________________________________________________________    Example 23            Preparation Example 1                       MA-100   PGMEA    Example 24         MA-220   (propylene glycol mono-    Example 25            Preparation Example 2                       MA-100   methyl ether acetate)    Example 26         MA-220    Comp. Ex. 33            Preparation Example 3                       MA-100    Comp. Ex. 34       MA-220    Comp. Ex. 35            Styrene/acrylic acid resin                       MA-100    Comp. Ex. 36            (acid value: 200,                       MA-220            Mw: 5,000    Comp. Ex. 37            Benzyl methacrylate/                       MA-100            methacrylic acid resin                       MA-220            (acid value: 200,            Mw: 10,000)    __________________________________________________________________________

                  TABLE 4    ______________________________________            Foreign matters on            the resist film                       Sensitivity                                  Resolution    ______________________________________    Example 23              Nil          2000 mj    20μ    Example 24              Nil          2000 mj    20μ    Example 25              Nil          2500 mj    20μ    Example 26              Nil          2500 mj    20μ    Comp. Ex. 33              Observed     4000 mj    50μ    Comp. Ex. 34              Observed     4000 mj    50μ    Comp. Ex. 35              Observed     5000 mj    >50μ    Comp. Ex. 36              Observed     5000 mj    >50μ    Comp. Ex. 37              Observed     Impossible to form an image              (large amount)    Comp. Ex. 38              Observed     Impossible to form an image              (large amount)    ______________________________________

As described in the foregoing, the composition of the present inventionis very useful not only for forming colored patterns of red, green andblue for a color filter but also for forming a black matrix.

INDUSTRIAL APPLICABILITY

The polymerizable composition of the present invention is highlysensitive and excellent in chemical resistance, whereby a color filterof a high quality can be produced without a protective film such as anoxygen-shielding film.

We claim:
 1. A polymerizable composition for a color filter, whichcomprises a (meth)acrylate copolymer containing alicyclic (meth)acryloylgroups in its side chains, a compound having at least one ethylenicallyunsaturated double bond, a photopolymerization initiator and a colorant;said photopolymerization initiator being a combination of an imidazolecompound and an aminobenzene derivative.
 2. The polymerizablecomposition for a color filter according to claim 1, wherein thephotopolymerization initiator system further contains an aromaticmercapto compound.
 3. The polymerizable composition for a color filteraccording to claim 1, wherein the colorant comprises a red, green orblue pigment and wherein the ratio of P/V is within a range of from 0.15to 0.6, where P is the content by weight of a red, green or bluepigment, and V is the content by weight of the solid content other thanthe pigment.
 4. A color filter having an image provided on a substrate,said color filter being formed from a polymerizable compositioncomprising a (meth)acrylate copolymer containing alicyclic(meth)acryloyl groups in its side chains, a compound having at least oneethylenically unsaturated double bond, a photopolymerization initiatorand a colorant; wherein said photopolymerization initiator is acombination of an imidazole compound and an aminobenzene derivative. 5.The color filter according to claim 4, wherein the photopolymerizationinitiator system further contains an aromatic mercapto compound.
 6. Thecolor filter according to claim 4, wherein the colorant comprises a red,green or blue pigment and wherein the ratio of P/V is within a range offrom 0.15 to 0.6, where P is the content by weight of a red, green orblue colorant, and V is the content by weight of the solid content otherthan the colorant.